Allows configuring the watchdog signal (with a default of SIGABRT).
This allows an alternative to SIGABRT when coredumps are not desirable.
Appropriate references to SIGABRT or aborting were renamed to reflect
more liberal watchdog signals.
Closes#8658
Previously, we'd act immediately on StopWhenUnneeded= when a unit state
changes. With this rework we'll maintain a queue instead: whenever
there's the chance that StopWhenUneeded= might have an effect we enqueue
the unit, and process it later when we have nothing better to do.
This should make the implementation a bit more reliable, as the unit notify event
cannot immediately enqueue tons of side-effect jobs that might
contradict each other, but we do so only in a strictly ordered fashion,
from the main event loop.
This slightly changes the check when to consider a unit "unneeded".
Previously, we'd assume that a unit in "deactivating" state could also
be cleaned up. With this new logic we'll only consider units unneeded
that are fully up and have no job queued. This means that whenever
there's something pending for a unit we won't clean it up.
RootImage= may require the following settings
```
DeviceAllow=/dev/loop-control rw
DeviceAllow=block-loop rwm
DeviceAllow=block-blkext rwm
```
This adds the following settings implicitly when RootImage= is
specified.
Fixes#9737.
Usecase is to allow changing the final kill from SIGKILL to SIGQUIT which
should create a core dump useful for debugging why the service didn't stop
with the SIGTERM
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Since bb28e68477 parsing failures of
certain unit file settings will result in load failures of units. This
introduces a new load state "bad-setting" that is entered in precisely
this case.
With this addition error messages on bad settings should be a lot more
explicit, as we don't have to show some generic "errno" error in that
case, but can explicitly say that a bad setting is at fault.
Internally this unit load state is entered as soon as any configuration
loader call returns ENOEXEC. Hence: config parser calls should return
ENOEXEC now for such essential unit file settings. Turns out, they
generally already do.
Fixes: #9107
This is very similar to the existing unit method coldplug() but is
called a bit later. The idea is that that coldplug() restores the unit
state from before any prior reload/restart, i.e. puts the deserialized
state in effect. The catchup() call is then called a bit later, to
catch up with the system state for which we missed notifications while
we were reloading. This is only really useful for mount, swap and device
mount points were we should be careful to generate all missing unit
state change events (i.e. call unit_notify() appropriately) for
everything that happened while we were reloading.
This reworks how systemd tracks processes on cgroupv1 systems where
cgroup notification is not reliable. Previously, whenever we had reason
to believe that new processes showed up or got removed we'd scan the
cgroup of the scope or service unit for new processes, and would tidy up
the list of PIDs previously watched. This scanning is relatively slow,
and does not scale well. With this change behaviour is changed: instead
of scanning for new/removed processes right away we do this work in a
per-unit deferred event loop job. This event source is scheduled at a
very low priority, so that it is executed when we have time but does not
starve other event sources. This has two benefits: this expensive work is
coalesced, if events happen in quick succession, and we won't delay
SIGCHLD handling for too long.
This patch basically replaces all direct invocation of
unit_watch_all_pids() in scope.c and service.c with invocations of the
new unit_enqueue_rewatch_pids() call which just enqueues a request of
watching/tidying up the PID sets (with one exception: in
scope_enter_signal() and service_enter_signal() we'll still do
unit_watch_all_pids() synchronously first, since we really want to know
all processes we are about to kill so that we can track them properly.
Moreover, all direct invocations of unit_tidy_watch_pids() and
unit_synthesize_cgroup_empty_event() are removed too, when the
unit_enqueue_rewatch_pids() call is invoked, as the queued job will run
those operations too.
All of this is done on cgroupsv1 systems only, and is disabled on
cgroupsv2 systems as cgroup-empty notifications are reliable there, and
we do not need SIGCHLD events to track processes there.
Fixes: #9138
This way we don't need to repeat the argument twice.
I didn't replace all instances. I think it's better to leave out:
- asserts
- comparisons like x & y == x, which are mathematically equivalent, but
here we aren't checking if flags are set, but if the argument fits in the
flags.
The function is similar to path_kill_slashes() but also removes
initial './', trailing '/.', and '/./' in the path.
When the second argument of path_simplify() is false, then it
behaves as the same as path_kill_slashes(). Hence, this also
replaces path_kill_slashes() with path_simplify().
This adds a flags parameter to unit_notify() which can be used to pass
additional notification information to the function. We the make the old
reload_failure boolean parameter one of these flags, and then add a new
flag that let's unit_notify() if we are configured to restart the
service.
Note that this adjusts behaviour of systemd to match what the docs say.
Fixes: #8398
When I see "test", I have to think three times what the return value
means. With "below" this is immediately clear. ratelimit_below(&limit)
sounds almost like English and is imho immediately obvious.
(I also considered ratelimit_ok, but this strongly implies that being under the
limit is somehow better. Most of the times this is true, but then we use the
ratelimit to detect triple-c-a-d, and "ok" doesn't fit so well there.)
C.f. a1bcaa07.
Scope units are populated from PIDs specified by the bus client. We do
that when a scope is started. We really shouldn't allow scopes to be
started multiple times, as the PIDs then might be heavily out of date.
Moreover, clients should have the guarantee that any scope they allocate
has a clear runtime cycle which is not repetitive.
Double newlines (i.e. one empty lines) are great to structure code. But
let's avoid triple newlines (i.e. two empty lines), quadruple newlines,
quintuple newlines, …, that's just spurious whitespace.
It's an easy way to drop 121 lines of code, and keeps the coding style
of our sources a bit tigther.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
Currently we add target dependencies while we are loading units. This
can create ordering loops even if configuration doesn't contain any
loop. Take for example following configuration,
$ systemctl get-default
multi-user.target
$ cat /etc/systemd/system/test.service
[Unit]
After=default.target
[Service]
ExecStart=/bin/true
[Install]
WantedBy=multi-user.target
If we encounter such unit file early during manager start-up (e.g. load
queue is dispatched while enumerating devices due to SYSTEMD_WANTS in
udev rules) we would add stub unit default.target and we order it Before
test.service. At the same time we add implicit Before to
multi-user.target. Later we merge two units and we create ordering cycle
in the process.
To fix the issue we will now never add any target dependencies until we
loaded all the unit files and resolved all the aliases.
This macro will read a pointer of any type, return it, and set the
pointer to NULL. This is useful as an explicit concept of passing
ownership of a memory area between pointers.
This takes inspiration from Rust:
https://doc.rust-lang.org/std/option/enum.Option.html#method.take
and was suggested by Alan Jenkins (@sourcejedi).
It drops ~160 lines of code from our codebase, which makes me like it.
Also, I think it clarifies passing of ownership, and thus helps
readability a bit (at least for the initiated who know the new macro)
Let's better check this inside of the call than before it, so that we
never issue this while reloading, even should these calls be called due
to other reasons than just the unit notify.
This makes sure the reload state is unset a bit earlier in
manager_reload() so that we can safely call this function from there and
they do the right thing.
Follow-up for e63ebf71ed.
path_is_normalized() will reject paths longer than 4095 bytes, so it's better
to not create a stack variable of unbounded size, but instead do the check first
and only then do that allocation.
Also use _cleanup_ to make things a bit shorter.
https://oss-fuzz.com/v2/issue/5424177403133952/7000
manager_recheck_journal() and manager_recheck_dbus() would be called to early
while we were deserialiazing units, before the systemd-journald.service and
dbus.service have been deserialized. In effect we'd disable logging to the
journald and close the bus connection. The first is not very noticable, it
mostly means that logs emitted during deserialization are lost. The second is
more noticeable, because manager_recheck_dbus() would call bus_done_api() and
bus_done_system() and close dbus connections. Logging and bus connection would
then be restored later after the respective units have been deserialized.
This is easily reproduced by calling:
$ sudo gdbus call --system --dest org.freedesktop.systemd1 --object-path /org/freedesktop/systemd1 --method "org.freedesktop.systemd1.Manager.Reload"
which works fine before 8559b3b75c, and then starts failing with:
Error: GDBus.Error:org.freedesktop.DBus.Error.NoReply: Remote peer disconnected
None of this should happen, and we should delay changing state until after
deserialization is complete when reloading. manager_reload() already included
the calls to manager_recheck_journal() and manager_recheck_dbus(), so the
connection state will be updated after deserialization during reloading is done.
Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1554578.
So, the kernel's management of cgroup/BPF programs is a bit misdesigned:
if you attach a BPF program to a cgroup and close the fd for it it will
stay pinned to the cgroup with no chance of ever removing it again (or
otherwise getting ahold of it again), because the fd is used for
selecting which BPF program to detach. The only way to get rid of the
program again is to destroy the cgroup itself.
This is particularly bad for root the cgroup (and in fact any other
cgroup that we cannot realistically remove during runtime, such as
/system.slice, /init.scope or /system.slice/dbus.service) as getting rid
of the program only works by rebooting the system.
To counter this let's closely keep track to which cgroup a BPF program
is attached and let's implicitly detach the BPF program when we are
about to close the BPF fd.
This hence changes the bpf_program_cgroup_attach() function to track
where we attached the program and changes bpf_program_cgroup_detach() to
use this information. Moreover bpf_program_unref() will now implicitly
call bpf_program_cgroup_detach().
In order to simplify things, bpf_program_cgroup_attach() will now
implicitly invoke bpf_program_load_kernel() when necessary, simplifying
the caller's side.
Finally, this adds proper reference counting to BPF programs. This
is useful for working with two BPF programs in parallel: the BPF program
we are preparing for installation and the BPF program we so far
installed, shortening the window when we detach the old one and reattach
the new one.
Before this change all unit types would default to "private" in the
system service manager and "inherit" to in the user service manager.
With this change this is slightly altered: non-service units of the
system service manager are now run with KeyringMode=shared. This appears
to be the more appropriate choice as isolation is not as desirable for
mount tools, which regularly consume key material. After all mounts are
a shared resource themselves as they appear system-wide hence it makes a
lot of sense to share their key material too.
Fixes: #8159
When various references to the unit were dropped during cleanup in unit_free(),
add_to_gc_queue() could be called on this unit. If the unit was previously in
the gc queue (at the time when unit_free() was called on it), this wouldn't
matter, because it'd have in_gc_queue still set even though it was already
removed from the queue. But if it wasn't set, then the unit could be added to
the queue. Then after unit_free() would deallocate the unit, we would be left
with a dangling pointer in gc_queue.
A unit could be added to the gc queue in two places called from unit_free():
in the job_install calls, and in unit_ref_unset(). The first was OK, because
it was above the LIST_REMOVE(gc_queue,...) call, but the second was not, because
it was after that. Move the all LIST_REMOVE() calls down.
We would free stuff like the names of the unit first, and then recurse
into other structures to remove the unit from there. Technically this
was OK, since the code did not access the name, but this makes debugging
harder. And if any log messages are added in any of those functions, they
are likely to access u->id and such other basic information about the unit.
So let's move the removal of this "basic" information towards the end
of unit_free().
A .socket will reference a .service unit, by registering a UnitRef with the
.service unit. If this .service unit has the .socket unit listed in Wants or
Sockets or such, a cycle will be created. We would not free this cycle
properly, because we treated any unit with non-empty refs as uncollectable. To
solve this issue, treats refs with UnitRef in u->refs_by_target similarly to
the refs in u->dependencies, and check if the "other" unit is known to be
needed. If it is not needed, do not treat the reference from it as preventing
the unit we are looking at from being freed.
No functional change.
The source unit manages the reference. It allocates the UnitRef structure and
registers it in the target unit, and then the reference must be destroyed
before the source unit is destroyed. Thus, is should be OK to include the
pointer to the source unit, it should be live as long as the reference exists.
v2:
- rename refs to refs_by_target
